Absolutely. The power supply you have (12V 18A) simply indicates that it can withstand higher current loads; or up to 18A. If you go over this current, the voltage will begin to drop significantly. Since you only require 13.3A, that is well below the maximum current rating.

Well, that is true if the power supply is a regulated one. If not you will soon find out that the only truth will be the smoke out of your system.
If the power supply is regulated then its output voltage is held constant regardless of the output current (up to the rated value of course). However, if the power supply is unregulated the output voltage will equal the rated voltage only if the current drawn is equal to the rated current. Always use regulated power supplies for electronic equipment.